Environmental Hazard: Deforestation – JSS3 Basic Science Lesson Note (First Term)

Deforestation is defined as the clearing of forest wood for farming or purposes without immediate replanting. This act of cutting down trees indiscriminately by the activities of man is encouraged by the following factors;

-Bush burning

-Building of schools, houses, etc.

-felling of trees for firewood

-Construction of roads and bridges.

 Reasons for Deforestation

-Production of timbers for woodwork

-Production of firewood and charcoal for domestic and industrial purposes.

-Extension or urbanization of towns and cities.

-Establishment of industries, markets, churches, houses, mosques, etc.

-Construction of roads and bridges.

-Overgrazing of grasses and small trees by big animals

 Effects of Deforestation on the Environment

-Forests are wind-breakers, when they are destroyed it gives way to wind effects.

-It enhances soil erosion which destroys farmland and buildings.

-When forests are destroyed, it increases the concentration of carbon (iv) oxide in the atmosphere which in turn depletes the ozone layer and also cause the greenhouse effect.

-The large concentration of carbon (iv) oxide in the atmosphere causes what is known as” global warming”

-It exposes the soil to intense evaporation of soil water and nutrients.

-It can lead to the extinction of some species of plants

-It may lead to migration and extinction of arboreal animals.

-It may also lead to the loss of forest resources such as resins, bark, fruits, honey, mushrooms, and medicinal plants.

-It can lead to a scarcity of wood.

-It may lead to desertification.

 Ways Controlling Deforestation

 -By afforestation program (planting of trees where they have not existed before)

-By reforestation-This is the process of replanting trees where they were originally present

-Use of alternative source or heat

-Establishment of wild-life park and game reserves.

-Adoption of modern methods of cattle rearing.

 Government Regulations against Deforestation.

-Restriction of logging and implementation of a compulsory tree planting program for all loggers.

-Increase charges and convictions against indiscriminate logging.

-Public authorities should impose regulative instruments based on a “command and control” approach

-The government should have forest areas protected by law.

ASSIGNMENT

1. Cutting down of trees and clearing of forests indiscriminately is called  A. afforestation  B. deforestation  C. regulation  D. conservation
2. Forests provide life for………… wildlife   A. shelter  B.poison  C. money  D. roads

3……………….. is one of the dangers of deforestation   A.good soil   B.good road  C.increase in population  C. Extinction of wildlife

4. A set of rules by the government to control excessive destruction of  forestry is known as   A. forest reserve   B.forest regulation  C.forest destruction  D. forest activities
5. All of these are regulations for forestry except   A.practising bush burning  B.prohibition of poaching in reserve areas  C.enactment of laws against cutting of trees  D.establisment of forest game reserve

6a.Define deforestation

b.State four reasons why people cut down trees

1. State three effects of clearing forests on wildlife